.TH "QwtSyntheticPointData" 3 "Fri Apr 15 2011" "Version 6.0.0" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtSyntheticPointData \- 
.PP
Synthetic point data.  

.SH SYNOPSIS
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.PP
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\fC#include <qwt_series_data.h>\fP
.PP
Inherits \fBQwtSeriesData< QPointF >\fP.
.SS "Public Member Functions"

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.RI "\fBQwtSyntheticPointData\fP (size_t size, const \fBQwtInterval\fP &=\fBQwtInterval\fP())"
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.RI "void \fBsetSize\fP (size_t size)"
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.RI "size_t \fBsize\fP () const "
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.RI "void \fBsetInterval\fP (const \fBQwtInterval\fP &)"
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.RI "\fBQwtInterval\fP \fBinterval\fP () const "
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.RI "virtual QRectF \fBboundingRect\fP () const "
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.RI "virtual QPointF \fBsample\fP (size_t i) const "
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.RI "virtual double \fBy\fP (double x) const =0"
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.RI "virtual double \fBx\fP (uint index) const "
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.RI "virtual void \fBsetRectOfInterest\fP (const QRectF &)"
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.RI "QRectF \fBrectOfInterest\fP () const "
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.SH "Detailed Description"
.PP 
Synthetic point data. 

\fBQwtSyntheticPointData\fP provides a fixed number of points for an interval. The points are calculated in equidistant steps in x-direction.
.PP
If the interval is invalid, the points are calculated for the 'rect of interest', what normally is the displayed area on the plot canvas. In this mode you get different levels of detail, when zooming in/out.
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\fBExample\fP
.RS 4

.RE
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The following example shows how to implement a sinus curve.
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.nf

#include <cmath>
#include <qwt_series_data.h>
#include <qwt_plot_curve.h>
#include <qwt_plot.h>
#include <QtWidgets/qapplication.h>

class SinusData: public QwtSyntheticPointData
{
public:
    SinusData():
        QwtSyntheticPointData(100)
    {
    }
    virtual double y(double x) const
    {
        return qSin(x);
    }
};

int main(int argc, char **argv)
{
    QApplication a(argc, argv);

    QwtPlot plot;
    plot.setAxisScale(QwtPlot::xBottom, 0.0, 10.0);
    plot.setAxisScale(QwtPlot::yLeft, -1.0, 1.0);

    QwtPlotCurve *curve = new QwtPlotCurve("y = sin(x)");
    curve->setData(SinusData());
    curve->attach(&plot);

    plot.show();
    return a.exec();
}
   .fi
.PP
 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "QwtSyntheticPointData::QwtSyntheticPointData (size_tsize, const \fBQwtInterval\fP &interval = \fC\fBQwtInterval\fP()\fP)"Constructor
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\fBParameters:\fP
.RS 4
\fIsize\fP Number of points 
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\fIinterval\fP Bounding interval for the points
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\fBSee also:\fP
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\fBsetInterval()\fP, \fBsetSize()\fP 
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.SH "Member Function Documentation"
.PP 
.SS "QRectF QwtSyntheticPointData::boundingRect () const\fC [virtual]\fP"
.PP
Calculate the bounding rect. This implementation iterates over all points, what could often be implemented much faster using the characteristics of the series. When there are many points it is recommended to overload and reimplement this method using the characteristics of the series ( if possible ).
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\fBReturns:\fP
.RS 4
Bounding rectangle 
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Implements \fBQwtSeriesData< QPointF >\fP.
.SS "\fBQwtInterval\fP QwtSyntheticPointData::interval () const"\fBReturns:\fP
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Bounding interval 
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\fBSee also:\fP
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\fBsetInterval()\fP, \fBsize()\fP 
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.SS "QRectF QwtSyntheticPointData::rectOfInterest () const"\fBReturns:\fP
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'rect of interest' 
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\fBSee also:\fP
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\fBsetRectOfInterest()\fP 
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.SS "QPointF QwtSyntheticPointData::sample (size_tindex) const\fC [virtual]\fP"Calculate the point from an index
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\fBParameters:\fP
.RS 4
\fIindex\fP Index 
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\fBReturns:\fP
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QPointF(x(index), y(x(index)));
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\fBWarning:\fP
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For invalid indices ( index < 0 || index >= \fBsize()\fP ) (0, 0) is returned. 
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Implements \fBQwtSeriesData< QPointF >\fP.
.SS "void QwtSyntheticPointData::setInterval (const \fBQwtInterval\fP &interval)"Set the bounding interval
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\fBParameters:\fP
.RS 4
\fIinterval\fP Interval 
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\fBSee also:\fP
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\fBinterval()\fP, \fBsetSize()\fP 
.RE
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.SS "void QwtSyntheticPointData::setRectOfInterest (const QRectF &rect)\fC [virtual]\fP"Set a the 'rect of interest'
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\fBQwtPlotSeriesItem\fP defines the current area of the plot canvas as 'rect of interest' ( \fBQwtPlotSeriesItem::updateScaleDiv()\fP ).
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If \fBinterval()\fP.isValid() == false the x values are calculated in the interval rect.left() -> rect.right().
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\fBSee also:\fP
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\fBrectOfInterest()\fP 
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Reimplemented from \fBQwtSeriesData< QPointF >\fP.
.SS "void QwtSyntheticPointData::setSize (size_tsize)"Change the number of points
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\fBParameters:\fP
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\fIsize\fP Number of points 
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\fBSee also:\fP
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\fBsize()\fP, \fBsetInterval()\fP 
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.SS "size_t QwtSyntheticPointData::size () const\fC [virtual]\fP"\fBReturns:\fP
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Number of points 
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\fBSee also:\fP
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\fBsetSize()\fP, \fBinterval()\fP 
.RE
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Implements \fBQwtSeriesData< QPointF >\fP.
.SS "double QwtSyntheticPointData::x (uintindex) const\fC [virtual]\fP"Calculate a x-value from an index
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x values are calculated by deviding an interval into equidistant steps. If !interval().isValid() the interval is calculated from the 'rect of interest'.
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\fBSee also:\fP
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\fBinterval()\fP, \fBrectOfInterest()\fP, \fBy()\fP 
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.SS "virtual double QwtSyntheticPointData::y (doublex) const\fC [pure virtual]\fP"Calculate a y value for a x value
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\fBParameters:\fP
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\fIx\fP x value 
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\fBReturns:\fP
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Corresponding y value 
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.SH "Author"
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